Auto companies expend enormous effort calibrating their vehicle engines to achieve an optimum level of performance relative to driver expectation. Horsepower, torque, and fuel economy are balanced across a complex set of operating circumstances prior to governmental certification. However, the way in which a vehicle is driven can have a considerable impact on fuel economy. For example, the 2006 model of the Ford F-150 4×4 5.4 L pickup truck has an EPA rating of 14 mpg in the city, 18 mpg on the highway and 16 mpg for a combination of city and highway driving. Yet, through judicious driving, it is possible to achieve more than 20 mpg in a real-world mix of city and highway driving. In other words, a fuel economy improvement of over 25% from the average can be achieved by a driver who wants to improve fuel economy. In comparison, GM announced on Apr. 30, 2006 that its 2008 model dual-mode hybrid Tahoe SUV will achieve 25% better fuel economy in combined city and highway driving over its conventional Tahoe SUV. While clearly not an apples-to-apples comparison, it should be appreciated that a more carefully controlled driving style can achieve a meaningful fuel economy benefit without any added cost.
Tips for fuel efficient driving can easily be found on the Internet. For example, Shell Oil's Media Centre site states that aggressive driving can use as much as a third more fuel than sensible driving. This is analogous to rolling back the price of gasoline from $3/gallon to $2.25/gallon for an aggressive driver who adopts a more sensible driving style. In this regard, consumers are recommended to avoid accelerating or braking too hard, use cruise control, turn off the engine when waiting in a queue and so forth. Similarly, edmunds.com includes an article entitled “Driving Tips” that asserts up to 37% better fuel economy can be achieved through a change in driving habits (with an average savings of 31%). Their recommendations are similar to those by Shell, and specific fuel economy improvements are provided for each tip. For example, driving at a lower speed is said to achieve an average fuel economy savings of 12%, while using cruise control is said to achieve an average fuel savings of 7%. However, as pointed out in the Eco-Driving tips on the Ford Motor Company sponsored site www.drivingskillsforlife.com, cruise control should not be used on hilly terrain where the goal is to maximize fuel economy. The Eco-Driving module from this site provides a considerable amount of information in support of environmentally friendly driving. For example, the Eco-Driving module states that fuel consumption increases rapidly at speeds above 60 mph and that acceleration accounts for nearly 50% of a vehicle's energy consumption in city driving conditions. While such general driving tips are unquestionably instructive, drivers are still essentially left on their own to guess how best to increase the fuel economy for their specific vehicles in any number of different driving situations.
Some automakers have offered models where the driver could switch between different modes of powertrain operation. However, this is typically achieved by adjusting the shift points of the transmission, and the goal is to increase power at the expense of fuel economy. In contrast, a control method for fuel economy has been proposed in German Patent Application Publication No. DE10218012. Under this approach, the driver is able to set a variable for fuel consumption and the onboard control system will then seek to achieve it. However, this may lead to changes in vehicle performance that do not meet with driver expectation.
While most drivers understand that quick accelerations and high speeds hurt fuel economy, vehicles today are not adequately equipped to help the driver improve fuel economy. Typically, a sliding-scale gauge or numerical mpg display is all that is provided to give the driver an indication of instantaneous or average fuel economy. Such indicators can be easily ignored by the driver. Additionally, in some vehicles equipped with a standard (stick-shift) transmission, a shift light has been provided to enable the driver to know when to shift gears without having to look at the tachometer. But, shifting is only one aspect of driving style and a shift light may not be the best way to communicate with the driver.
Visual displays have also been recommended in the patent art. For example, Japanese Patent Publication No. JP2002370560 recommends the use of an instrument cluster or navigational display to indicate an optimum accelerator pedaling value to the driver. Such a solution would require that the driver repeatedly alternate his or her focus from the road to the in-vehicle display and back again in an attempt to achieve the optimum value displayed. Another visual display approached is recommended in U.S. Pat. No. 6,092,021. In this case, prompting messages are displayed when inefficient fuel use is detected, such as “DRIVE STEADY SPEED.” However, such commands may not exactly lead to customer satisfaction, and by definition, these message arrive after the fact.
Some announcements have also been made by automakers about their experiments to help drivers, but as yet no commercially available solution exists for consumers. For example, The New Scientist reported on Mar. 22, 2004 that DaimlerChrysler was experimenting with a vibrating accelerator pedal to alert a driver when to slow down. The prototype was said to use GPS to anticipate a curve in the road ahead, vehicle-detecting radar to help avoid getting too close to any vehicle in the front, a PC to assimilate these measurements and a small actuator fixed under the accelerator pedal to lightly vibrate a small piston against the underside of the pedal rubber when it was time to decelerate. Vibration alert was chosen, because DaimlerChrysler found that drivers would react much faster to a vibration than they would to a dashboard light.
Another experiment was conducted by Volkswagen of America and Stanford University in a 2003-2004 project entitled “Symbiotic Car: Haptic Feedback Accelerator Pedal.” In this case, the driver was able to select between a fuel economy mode, a performance shifting mode, and a speeding/tailgating mode using a control interface in a 2003 VW GTI VR6. Based on the detected vehicle speed and engine speed, a software program determined the appropriate haptic output: a force against the driver's foot if he or she was speeding and vibration cues if the system was in shifting mode. The prototype system included a DC motor and cable assembly that would pull on the accelerator pedal in order to induce a force opposing the driver's foot. A microcontroller would send a signal to the motor specifying which type of haptic feedback to create, whether to create a vibration (˜49 Hz) or a continuous force (zero to five pounds) sensation at the accelerator pedal. The motor was mounted above the gas pedal. A cable was attached to around a gear head mounted on the motor's shaft and was connected to the gas pedal using an eyebolt. The results of this experiment indicated that the drivers liked having the shifting points cued to them only if they could choose the shift point.
Of course, the concept of vibrating the accelerator pedal can also be found in the patent art, such as U.S. Pat. Nos. 5,113,721 and 6,925,425, French Patent Application Publication No. FR2828155, and U.S. Patent Application Publication Nos. 2005/0110348 and 2005/0021226. However, the lack of a commercially available solution in the market today indicates that the problem to solve is complex. For example, the solution must be effective to increase fuel economy, but not so intrusive as to discourage use or adversely impact customer satisfaction. As Ford's patented BeltMinder™ system has demonstrated, invention is often necessary to encourage the use of even a device as beneficial as a seatbelt. The solution should also be capable of causing more than a temporary change in driving style, while still giving the driver an exhilarating experience. The solution should also be applicable to current production vehicles, as well as to millions of vehicles that are already in use. The solution should be easy to use, not need to interfere with normal vehicle operation, be inexpensive to install and not require recertification of the vehicle or a violation of the vehicle's warranty. Additionally, the solution should not distract the driver or require constant attention by the driver to achieve its fuel economy goal. Ideally, the solution will enable a consumer to purchase a vehicle large enough for their needs, but also enable the driver to operate the vehicle in a way that approaches the fuel efficiency of a smaller vehicle. In other words, the solution should be such as to enable the driver to retain and always be able to use all of the powertrain capability of the vehicle whenever required, but not leave the driver to guess how best to increase fuel economy otherwise.
Accordingly, a haptic apparatus and coaching method are advantageously provided to enable and encourage the driver to improve the fuel economy of the vehicle—without having to take control away from the driver.
It is also an advantage that this haptic apparatus that can be installed in millions of existing vehicles, as well as in future production vehicles.
It is another advantage that the haptic apparatus and coaching method will help promote safe driving habits, as well as reduce brake and tire wear.
It is a further advantage that the haptic apparatus and coaching method will self adjust to the specific vehicle being driven.
It is yet another advantage that the haptic apparatus and coaching method will enable the driver to adjust the level of fuel economy desired to be achieved without requiring the vehicle to be recertified.
In order to achieve the foregoing advantages, an apparatus is provided that includes a haptic actuator operatively associated with a pedal assembly of the vehicle, a human-machine interface (HMI) for enabling the driver to select between a plurality of fuel savings settings, and a controller configured to provide coaching feedback to the driver through the haptic actuator when the vehicle crosses at least one of a plurality of speed and acceleration thresholds responsive to the HMI setting. Additionally, the advantageous coaching method provides haptic-based feedback that will not interfere with the operation of the vehicle. Rather, this method of closed-loop feedback provides a timely signal to the driver in a way that will encourage a change in driver style over time, such as backing off the accelerator pedal to accelerate at a lower rate and braking earlier with less intensity. As not all driver preferences are the same under all conditions, the HMI selector will help coach the driver by providing feedback that best fits their driving preference at the particular time.
The above features and advantages, as well as others, will be readily apparent from the following detailed description of the preferred embodiments. Further advantages and features will be seen from the drawings, which are summarized briefly below: